Liquid crystal display device

ABSTRACT

In a liquid crystal display device, a plurality of first light absorptive resin layer patterns, a plurality of metal layer patterns, a plurality of second light absorptive resin layer patterns, a transparent resin layer, and a plurality of transparent electrode patterns are laminated in this order on a surface of a first transparent substrate facing a liquid crystal layer; the plurality of the first light absorptive resin layer patterns, the plurality of the metal layer patterns, and the plurality of the second light absorptive resin layer patterns have openings formed therein, and are formed into the same shape when viewed in a laminating direction; the plurality of the metal layer patterns are arrayed in a first direction, being insulated from each other, the plurality of the transparent electrode patterns are arrayed in a second direction perpendicular to the first direction, being insulated from each other.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation application filed under 35 U.S.C.§111(a) claiming the benefit under 35 U.S.C. §§120 and 365(c) ofInternational Application No. PCT/JP2014/063835 filed on May 26, 2014,which is based upon and claims the benefit of priority of JapanesePatent Application No. 2014-038822, filed on Feb. 28, 2014, the entirecontents of them all are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a liquid crystal display device havinga liquid crystal panel incorporating a touch sensing function, andhaving a higher aperture ratio and good visibility. The presentinvention can provide a liquid crystal display device equipped with atouch sensing electrode that uses a low-resistance metal layer patternfavorable for an electrode for use in touch sensing, and has higherlight shielding properties of transmission light, the metal layerpattern exhibiting substantially black reflected color. In other words,the present invention relates to a so-called, in-cell liquid crystaldisplay device incorporating a capacitive touch sensing function in aliquid crystal cell.

BACKGROUND

In recent years, liquid crystal display devices or organic EL displaydevices have been required to have a high aperture ratio to achievebright display or low power consumption. To improve the contrast ratioof the display by dividing pixels, these display devices typically use ablack matrix formed by carbon dispersion or the like as a black colormaterial in a photosensitive resin.

(Light Shielding Properties of Black Matrix)

The black matrix, which is disposed dividing pixels to ensure displaycontrast, is typically formed on a transparent substrate such as glassusing a black resin with a large thickness of 1 μm (micrometer) or moreso as to obtain high light shielding properties. The black resin in thiscase is obtained by dispersing a color material such as carbon pigmentin a resin. The black matrix in a frame portion on four sides of adisplay area where pixels are arranged in a matrix pattern, i.e. theframe-like black matrix, is particularly required to have high lightshielding properties, i.e., high optical density of 5 or more, or 6 ormore in transmission measurement. Light transmitted from a backlightunit is likely to leak from the frame portion, and therefore the blackmatrix in the frame portion is required to have a higher optical densitythan that of the black matrix formed on the display area.

(Forming Black Matrix with Thin Lines)

In display devices for small-size mobile devices, such as cellularphones, displays are being formed with increasingly higher definitionsuch as 200 ppi (pixels per inch) or more, or 300 ppi or more.Accompanying this, black matrixes are required to have thinner lines, inaddition to the need to have high light shielding properties. If blackmatrixes achieve high definition, the pixel width unavoidably becomessmaller than 30 μm. It has been revealed that a smaller thickness of theblack matrixes adversely affects the flatness of the color filters. In ahigh-definition display device having 300 ppi or more, the black matrixneeds to have a line width of 4 μm or less.

For example, since black matrixes have high light shielding properties,it is difficult to stably manufacture a pattern of black matrixes with athin line having a width of 4 μm or smaller, by photolithography. If theblack matrix has light shielding properties, sufficient light does notenter in a thickness direction of the black matrix at light exposure.Therefore, the thin film that forms a black matrix easily peels off in aprocess of development or the like.

Moreover, from the viewpoint of alignment, it is very difficult to forma black matrix with a thin line width of 4 μm or less through two-stepphotolithography processes, i.e. to form it with two layers, for thepurpose of improving light resistance. Forming a black matrix throughtwo-step photolithography processes tends to cause variation of linewidth or display unevenness, due to alignment errors.

In typically used processing steps of color filters and the like, sincea plurality of screens are formed on a large-size transparent substrate,an alignment margin of ±2 μm, for example, is needed in general.Therefore, it has been difficult to form a black matrix by two-stepphotolithography processes.

(Touch Sensing Function in Display Device)

A method of enabling direct input to a liquid crystal display device oran organic EL display device is sought to be achieved, for example byattaching a capacitive touch panel to the display device, or providingelements suitable for touch sensing at portions of the display device,the portions being in contact with a liquid crystal layer, or the like.The method of providing elements suitable for touch sensing is called anin-cell method. For example, the in-cell method is based onelectrostatic capacitance, or a technique of using an optical sensor.

The technique based on electrostatic capacitance is often applied totouch sensing based on the in-cell technique which enables the displaydevice to acquire input using a pointer such as a finger or a styluspen. This method based on electrostatic capacitance needs severaltwo-set electrode groups for sensing electrostatic capacitance, asdisclosed in PTLs 1 to 5.

CITATION LIST Patent Literature

[PTL 1] JP-B-2653014

[PTL 2] JP-A-2009-540375

[PTL 3] JP-B-4816668

[PTL 4] WO 2013/089019A

[PTL 5] WO 2013/018736A

SUMMARY OF INVENTION Technical Problem

PTLs 1 to 5 have problems as shown below.

PTL 1 discloses two sets of electrode groups that enable input of aspatial coordinate by utilizing capacitive coupling of metals such as Al(aluminum) or Cr (chromium), as disclosed in paragraphs [0018] and[0019].

However, the technique of PTL 1 has many defects. For example, paragraph[0019] describes that the two sets of light-shielding electrodes serveas a black matrix, and that a conductor having light shieldingproperties is made of metal such as of Al or Cr. However, these metalshave high light reflectance, and hence reflected light is conspicuous ina bright room or outdoors where sun shines, and the quality of displayis significantly deteriorated. PTL 1 fails to disclose a positionalrelationship of the two sets of electrodes, with a black layer patternand a color filter, in a thickness direction of the display device. Thepattern in this case uses a black color material and is applied to manydisplay devices to obtain contrast in the display devices. Thus, PTL 1fails to sufficiently describe color display that involves transmissionand reflection.

Further, Al (aluminum) does not have alkali resistance, and thus isdifficult, for example, to harmonize with the photolithographic processof forming red, green and blue pixels (the process includes using analkaline developing solution).

More specifically, in a typically used color filtering process ofalkali-developing a colored pattern such as of red pixels using acolored photosensitive resin, Al dissolves in the alkaline developingsolution. Thus, Al is difficult to apply to the color filtering process.When Cr is concerned, if wet etching is adopted for pattern forming,there is a concern of environmental pollution caused by Cr ions. If dryetching is adopted, halogen gas used therein is a more dangerous risk.

PTL 2 proposes a configuration in which at least one touch element isdisposed on a surface of a TFT plate, which is a first substrate, facinga second substrate, as recited, for example, in claims 1 to 3, 35, 45and 60 of PTL 2. Claim 4 of PTL 2 recites a configuration in which aplurality of metal touch sensing electrodes are disposed on the back ofa black matrix.

The gist of the technique of PTL 2 is recited to some extent in claims 1to 3 of PTL 1. The technique of PTL 2 is important in that it explicitlyshows a specific configuration of a touch element associated with touchsensing. Besides paragraph [0015] of PTL 1, there is a description thatan electrode means for use as stylus input through charge detection alsoserves as a component of an AMLCD (active matrix liquid crystaldisplay).

However, the technique of PTL 2 fails to consider optimization of theliquid crystal display device, and particularly fails to considertransmittance. Moreover, PTL 2 fails to sufficiently consider atechnique relating to noise reduction in touch sensing, or to improvevisibility when the liquid crystal display device is viewed from anobserver.

In addition, regarding the plurality of metal touch sensitive electrodesdisposed on the back of the black matrix, there is no detaileddescription of the black matrix pattern and a pattern of the pluralityof metal touch sensitive electrodes. It can be understood from FIG. 57or 72 of PTL 2 that there is a difference in size between the blackmatrix pattern and the pattern of a metal or the like shown by referencesign M1. PTL 2 fails to disclose a technique of forming the black matrixpattern and the pattern of the metal or the like, with the same linewidth. For example, there is no specific description of achieving a highdefinition with pixels of 300 ppi or more.

PTL 2 is almost silent about a method of holding an electrostaticcapacitance across the pattern such as of a metal shown by referencesign M1 and a counter electrode made of ITO₂ or the like used for touchsensing, and specific measures for noise reduction or improvement of S/Nratio in touch sensing. Further, although light reflection from an ITOor a metal BM is incident on an observer's eye in a configuration shownin FIG. 36, for example, PTL 2 fails to consider a technique ofimproving visibility, with which reflectance of the black matrix shownin FIG. 57 is decreased to realize low reflectance. PTL 2 also fails toconsider light reflected from the liquid crystal shown by reference signM1 in FIG. 57 (retroreflection in a liquid crystal cell).

The technique of PTL 2 is not sufficient from the viewpoint oftransmittance required for serving as a liquid crystal display device,as well as the viewpoint of visibility for an observer and noisereduction or an S/N ratio in touch sensing.

PTL 3 discloses a technique of using a driving voltage for display,applied to a common electrode disposed in the vicinity of a liquidcrystal layer in a liquid crystal display device, as a driving signalfor a touch sensor. As disclosed in FIGS. 4, 5, 7, and 8 of PTL 3, thecommon electrode is disposed at a position farther from a pointer suchas a finger than a detection electrode is, and a driving signal (adriving electrode) is applied to the common electrode.

PTL 3 fails to disclose a configuration in which an electrode disposedat a position closer to a pointer such as a finger is used as a drivingelectrode associated with touch sensing. Further, PTL 3 also fails todisclose a technique of configuring the driving electrode used for touchsensing, by laminating a light absorptive resin layer and a copper alloyin this order from a position closer to the observer. The technique ofPTL 3 is not optimized from the viewpoint of transmittance needed whenserving as a liquid crystal display device, as well as the viewpoint ofvisibility for the observer and noise reduction or an S/N ratio in touchsensing.

PTL 4, as recited in claim 1 thereof, discloses a capacitive touch panelsubstrate, in which an electrostatic capacitance is generated byadjacently disposed first and second unit electrodes which are flushwith each other. For example, (a) and (b) of FIG. 3 of PTL 4 disclose aconfiguration in which a conductive layer 7 is laminated on aninsulating light-shielding layer 6.

Further, PTL 4 discloses that the substrate includes a portion where theinsulating light-shielding layer 6 is not formed, as shown in FIG. 1that is a cross section taken along the line A-A′ of FIG. 3 (a), and aportion where the conductive layer 7 is formed on the insulatinglight-shielding layer 6, as shown in FIG. 2 that is a cross sectiontaken along the line B-B′ of FIG. 3 (a).

In FIG. 2 of PTL 4, the insulating light-shielding layer 6 has a largewidth, and hence causes a problem of a decrease in aperture ratio ofpixel openings. In contrast, in FIG. 1, the conductive layer 7 isvisually recognized via a transparent insulating substrate, and hencelight reflected from the conductive layer 7 enters an observer's eye,causing a problem of significantly decreasing visibility. As describedin paragraph [0071] of PTL 4, the conductive layer 7 plays a role ofestablishing an electrical connection, via a contact hole, with aposition detection electrode 9 that transmits visible lighttherethrough, but does not play a role of performing capacitivedetection.

PTL 4 fails to disclose a configuration in which a sensing electrode,which is the position detection electrode 9, and a drive electrode arelaminated being perpendicular to each other on a surface of thetransparent insulating substrate contacting a liquid crystal, via aninsulating layer such as a transparent resin layer, for example. Inaddition, PTL 4 fails to disclose a technique of forming the insulatinglight-shielding layer 6 and the conductive layer 7 into the same shapeand dimension in plan view.

The technique disclosed in PTL 4 has a problem that the configuration isextremely complicated, including formation of the contact hole. From theviewpoint of an aperture ratio as well, it cannot be said that PTL 4proposes a touch panel substrate having good visibility.

PTL 5 discloses a display device that uses an oxide layer which containsan element selected from In, Ga, and Zn as a semiconductor layer of anactive element, and includes one frame period consisting of a firstperiod in which image data is written, and a second period in whichpositional detection of an object to be detected is sensed. In aposition detecting portion, a plurality of first electrodes are providedso as to intersect with a plurality of second electrodes. As shown inFIG. 4 or 24 of PTL 5, the plurality of first and second electrodes areadjacent to each other respectively in plan view, and are capacitivelycoupled, at their adjacent sites as recited in claim 3 of PTL 5.

FIG. 2 shows a pixel arrangement in a TFT substrate relating to thetechnique of PTL 5, in which pixels are arranged in a horizontaldirection and a vertical direction in plan view. FIGS. 4 and 24 disclosethe first and second electrodes which are divided by slits in a rhombuspattern and arrayed in a direction of about 45 degrees.

In the technique in PTL 5, the shape of the pixel electrodes, and thestate of positional alignment of the rhombus-shaped first and secondelectrodes in plan view are unclear. Further, there is no disclosure ofan optimal liquid crystal when the first and second electrodes, whichare defined by slits and arrayed in a direction of about 45 degrees, areused as common electrodes Com. When a vertically-aligned liquid crystalis assumed, the slits in the direction of about 45 degrees areconsidered to adversely affect the liquid crystal alignment ortransmittance of the liquid crystal, for example. As shown in paragraphs[0143] and [0144] or FIG. 13 of PTL 5, a conductive layer 27 and abridge electrode 7 are formed of the same metal layer. However, PTL 5fails to disclose a technique of configuring either the first electrodeor the second electrode with two layers made up of a metal layer and ablack matrix. For example, PTL 5 fails to disclose a driving electrodefor touch sensing in which a light absorptive resin layer pattern and ametal layer pattern having the same shape and dimension are laminatedwith each other.

In view of the circumstances as described above, it is desired that aliquid crystal display device having a touch sensing function hasperformance as described below, for example. Specifically, in order toreduce noise during a touch sensing operation of a pointer such as afinger or a stylus pen, it is desired that the plurality of capacitivetwo-set electrode groups described above have a low resistance. Inparticular, the plurality of electrode groups are required to be locatedat a position nearer to the pointer such as a finger, and the drivingelectrode used for touch sensing (i.e., the scanning electrode) isrequired to have a low resistance, so as to prevent waveform of drivingvoltage from being rounded. Moreover, it is desirable that a detectionelectrode perpendicular to the driving electrode also has a lowresistance.

A surface of the plurality of electrode groups applied to the displaydevice needs to have low reflectance. If the plurality of electrodegroups have high light reflectance (have reflectance which is not low),when bright daylight such as sunlight is incident on the display area ofthe display device, display quality is significantly deteriorated. Forexample, when one set of electrode groups is formed of a single layer ofaluminum or chromium, or has a two-layer structure formed of thesemetals and chromium oxide, external light reflectance becomes large,causing deterioration in display visibility. To decrease retroreflectedlight from a backlight unit provided to the back surface of an arraysubstrate of the liquid crystal display device, the surface of each ofthe plurality of electrode groups desirably has low reflectance.

In a configuration of the embodiments of the present invention describedbelow, transmittance of liquid crystal display is enhanced by using adriving electrode having a higher aperture ratio, a detection electrode(transparent electrode) ensuring transmittance, and a vertically-alignedliquid crystal layer driven by a longitudinal electric field, throughoutthe thickness of the display.

The present invention has been made in view of the above-describedproblems, and has a first object of providing a liquid crystal displaydevice having an improved aperture ratio, with a touch sensing functionbeing incorporated, and having a low-resistance driving electrode of ablack appearance, with good visibility and higher transmittance(aperture ratio).

The present invention has a second object of providing a liquid crystaldisplay device having improved or even high performance in detecting aposition of a pointer such as a finger, with a simple configuration andhigh accuracy.

Solution to Problem

To try to solve the above-described issues, the present inventionproposes a means below.

A liquid crystal display device in one aspect of the present inventionincludes: a display unit that has a display substrate, a liquid crystallayer, and an array substrate laminated therein in this order; and acontrol unit that controls the display unit and a touch sensingfunction, wherein the display substrate has a first transparentsubstrate, and has a plurality of first light absorptive resin layerpatterns having openings formed therein, a plurality of metal layerpatterns having openings formed therein, a plurality of second lightabsorptive resin layer patterns having openings formed therein, atransparent resin layer, and a plurality of transparent electrodepatterns that are electrically isolated, laminated in this order on asurface of the first transparent substrate, the surface of the firsttransparent substrate facing the liquid crystal layer, the plurality offirst light absorptive resin layer patterns, the plurality of metallayer patterns, and the plurality of second light absorptive resin layerpatterns are formed into the same shape and are in alignment, whenviewed in a laminating direction along which the display substrate, theliquid crystal layer, and the array substrate are laminated, theplurality of metal layer patterns are arrayed in a first directionperpendicular to the laminating direction, being insulated from eachother, the plurality of transparent electrode patterns are arrayed in asecond direction perpendicular to the laminating direction and the firstdirection, being insulated from each other, each metal layer pattern hasat least one of an alloy layer mainly containing copper, and a copperlayer, the array substrate has a second transparent substrate, and has apixel electrode, a thin film transistor, a metal wiring, and a pluralityof insulating layers provided on a surface of the second transparentsubstrate, the surface of the second transparent substrate facing theliquid crystal layer, the touch sensing function at least includessetting the plurality of the transparent electrode patterns to aconstant electrical potential, applying a touch driving voltage acrossthe plurality of transparent electrode patterns and the plurality ofmetal layer patterns, and detecting a change in electrostaticcapacitance across the metal layer patterns and the transparentelectrode patterns, and in driving the liquid crystal layer, theplurality of transparent electrode patterns are set to a constantelectrical potential, a liquid crystal driving voltage is applied acrossthe plurality of transparent electrode patterns and the pixel electrodeto drive the liquid crystal layer, and a frequency of the touch drivingvoltage is different from that of the liquid crystal driving voltage.

In the liquid crystal display device in one aspect of the presentinvention, it is preferable that the array substrate includes the pixelelectrode, and an auxiliary capacitance electrode disposed on anopposite side to the liquid crystal layer via the insulating layerscontacting the pixel electrode, each auxiliary capacitance electrodeforms, in plan view, an overlap with the pixel electrode and anextension of the auxiliary capacitance electrode, the extension beingextended from the pixel electrode, the overlaps as well as theextensions are line-symmetrically disposed with respect to a center linedividing the opening into two, and a voltage different from the liquidcrystal driving voltage is applied to each auxiliary capacitanceelectrode.

In the liquid crystal display device in one aspect of the presentinvention, it is preferable that the thin film transistor includes achannel layer that contains two or more metal oxides among gallium,indium, zinc, tin, and germanium.

In the liquid crystal display device in one aspect of the presentinvention, it is preferable that each metal layer pattern is configuredof a plurality of layers, and at least one of the plurality of layers isthe alloy layer.

In the liquid crystal display device in one aspect of the presentinvention, it is preferable that each metal layer pattern has the alloylayer, and an alloy element contained in the alloy layer is one or moreelements selected from magnesium, calcium, titanium, molybdenum, indium,tin, zinc, aluminum, beryllium, and nickel.

In the liquid crystal display device in one aspect of the presentinvention, it is preferable that each metal layer pattern is configuredof a plurality of layers, and among the plurality of layers, the layernearest to the second transparent substrate is a copper-indium alloylayer.

In the liquid crystal display device in one aspect of the presentinvention, it is preferable that auxiliary conductors having resistivitysmaller than resistivity of the plurality of transparent electrodepatterns are provided on the transparent electrode patterns.

In the liquid crystal display device in one aspect of the presentinvention, it is preferable that the openings of the first lightabsorptive resin layer patterns, the openings of the metal layerpatterns, and the openings of the second light absorptive resin layerpatterns are each provided with any of a red pixel formed of a redlayer, a green pixel formed of a green layer, and a blue pixel formed ofa blue layer, and the red pixel, the green pixel, and the blue pixel areinserted between the plurality of metal layer patterns and thetransparent resin layer in the laminating direction, and are arrangedadjacently to each other when viewed in the laminating direction.

In the liquid crystal display device in one aspect of the presentinvention, it is preferable that liquid crystal molecules contained inthe liquid crystal layer exhibit negative dielectric anisotropy and areinitially aligned in a vertical direction.

The electrodes associated with touch sensing, together with thedetection electrode and the driving electrode, are hereinaftercollectively referred to as a touch electrode.

As described in detail below, the driving electrode has a three-layerconfiguration including the first light absorptive resin layer, themetal layer, and the second light absorptive resin layer. In thedescription below, a driving electrode having the three-layerconfiguration may also be referred to as a black electrode, and apattern of the black electrode may also be referred to as a blackpattern.

Advantageous Effects of the Invention

One aspect of the present invention can increase an aperture ratio tothereby provide a liquid crystal display device that has improvedtransmittance and improved visibility, for example. Moreover, accordingto one aspect of the present invention, it is possible to provide aliquid crystal display device equipped with a black electrode that hasan improved or even high performance in detecting a position of thepointer such as a finger, and has a smaller resistance value and lowerreflectance, for example.

In one aspect of the present invention, the metal layer pattern isprovided thereon with the second light absorptive resin layer pattern.Provision of the second light absorptive resin layer can preventretroreflection of light in the liquid crystal cell. For example, if aplurality of metal wirings (including a source line, a gate line, andthe like) in the second transparent substrate of the array substrate aremade of copper or aluminum, retroreflection or diffused reflection oflight between the metal layer patterns disposed in the first transparentsubstrate can be prevented. If the thin film transistor is sensitive tolight, retroreflected light can be prevented from being incident on thinfilm transistor.

In addition, one aspect of the present invention proposes a touchelectrode flexibly adaptable up to a pixel size that is better suited toachieve a higher definition. This touch electrode, in contrast to anexternally-added touch panel, can support stylus input.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a liquid crystal display device,according to a first embodiment of the present invention.

FIG. 2 is a side cross-sectional view illustrating a display unit of theliquid crystal display device, according to the first embodiment of thepresent invention.

FIG. 3 is a plan view illustrating black electrodes of the liquidcrystal display device, according to the first embodiment of the presentinvention.

FIG. 4 is a plan view illustrating the black electrodes and transparentelectrode patterns of the liquid crystal display device, according tothe first embodiment of the present invention.

FIG. 5 is an enlarged plan view illustrating one pixel of an arraysubstrate of the liquid crystal display device, according to the firstembodiment of the present invention.

FIG. 6 is a schematic cross-sectional view illustrating a display unitof a liquid crystal display device, along with electric force lines,according to conventional art.

FIG. 7 is a schematic cross-sectional view illustrating the display unitof the liquid crystal display device, along with equipotential lines,according to conventional art.

FIG. 8 is a schematic cross-sectional view illustrating a display unitof a liquid crystal display device, along with equipotential lines,according to a modification of conventional art.

FIG. 9 is a plan view illustrating a positional relationship in aprincipal part of the liquid crystal display device, according to thefirst embodiment of the present invention.

FIG. 10 is a plan view illustrating a positional relationship in aprincipal part of the liquid crystal display device, according to thefirst embodiment of the present invention.

FIG. 11 is a flowchart illustrating a method of manufacturing asubstrate for the liquid crystal display device, according to the firstembodiment of the present invention.

FIG. 12 is a cross-sectional view illustrating effects of a touchelectrode of the liquid crystal display device, according to the firstembodiment of the present invention.

FIG. 13 is a cross-sectional view illustrating effects of the touchelectrode of the liquid crystal display device, according to the firstembodiment of the present invention.

FIG. 14 is a side cross-sectional view illustrating a display unit,according to a second embodiment of the present invention.

FIG. 15 is a plan view illustrating the display unit, according to thesecond embodiment of the present invention.

FIG. 16 is a cross-sectional view taken along the line A1-A1 of FIG. 15.

FIG. 17 is a cross-sectional view taken along the line A2-A2 of FIG. 15.

FIG. 18 is a side cross-sectional view illustrating a display unit,according to a fourth embodiment of the present invention.

FIG. 19 is a cross-sectional view illustrating effects of the displayunit, according to the fourth embodiment of the present invention.

DESCRIPTION OF REPRESENTATIVE EMBODIMENTS

With reference to the drawings, hereinafter will be described someembodiments of the present invention. In the description below,identical or substantially identical functions and components aredesignated with the same reference signs to omit duplicate descriptionor provide description only when needed. The embodiments describedherein are representative of the invention, and the invention is notlimited to these representative embodiments.

In each of the embodiments, characteristic portions will be described,omitting description, for example, of portions having no difference fromthe components of typically used display devices. In each of theembodiments, a liquid crystal display device will be described as a mainexample. However, as is occasionally described in the embodiments, thepresent invention can be similarly applied to other display devices suchas organic EL display devices.

First Embodiment

With reference to FIGS. 1 to 13, a first embodiment of a liquid crystaldisplay device according to the present invention will be described. Thescale ratio of thicknesses or dimension of components is varied betweenthe drawings as appropriate for the sake of clarity.

As shown in FIG. 1, a liquid crystal display device 100 of the presentembodiment includes a display unit 110, and a control unit 120 forcontrolling the display unit 110 and a touch sensing function.

As shown in FIG. 2, the display unit 110 has a configuration in which aliquid crystal display device substrate 22 (display substrate), a liquidcrystal layer 24, and an array substrate 23 are laminated in this order.The display unit 110 performs a display operation in a normally-blackmode. Specifically, the display unit 110 is configured by bonding afirst transparent substrate 10 of the liquid crystal display devicesubstrate 22, which will be described below, and a second transparentsubstrate 20 of the array substrate 23, which will be described below,such that they face each other via the liquid crystal layer 24.

The term “face each other” refers to that a surface of the transparentsubstrate 10 where a touch electrode such as a metal layer pattern 2,which will be described below, is formed, faces a surface of thetransparent substrate 20 each other where a functional element such as apixel electrode 25 or a thin film transistor 45, which will be describedbelow, is formed. The direction along which the liquid crystal displaydevice substrate 22, the liquid crystal layer 24, and the arraysubstrate 23 are laminated is defined as a laminating direction Z(vertical direction).

(Schematic Configuration of Liquid Crystal Display Device Substrate)

The liquid crystal display device substrate 22 has a configuration inwhich a plurality of first light absorptive resin layer patterns 1, aplurality of metal layer patterns 2, a plurality of second lightabsorptive resin layer patterns 3, a transparent resin layer 5, and aplurality of transparent electrode patterns 6 are laminated in thisorder on a main surface (surface) 10 a of the first transparentsubstrate 10, the main surface facing the liquid crystal layer 24. Asmentioned above, the light absorptive resin layer patterns 1 and 3, andthe metal layer pattern 2 sandwiched by the light absorptive resin layerpatterns 1 and 3 configure a black electrode 4.

A glass substrate is used, for example, as the first transparentsubstrate 10.

As shown in FIG. 3, when viewed parallel to the laminating direction Z(in plan view), the plurality of first light absorptive resin layerpatterns 1, the plurality of metal layer patterns 2, and the pluralityof second light absorptive resin layer patterns 3 are formed into thesame shape and completely aligned.

Specifically, the dimension is the same between the plurality of firstlight absorptive resin layer patterns 1, the plurality of metal layerpatterns 2, and the plurality of second light absorptive resin layerpatterns 3.

The shape is the same between the plurality of first light absorptiveresin layer patterns 1, the plurality of metal layer patterns 2, theplurality of second light absorptive resin layer patterns 3, and theplurality of black electrodes 4 obtained by laminating the plurality offirst light absorptive resin layer patterns 1, the plurality of metallayer patterns 2, and the plurality of second light absorptive resinlayer patterns 3. Accordingly, the following description is providedcentering on the configuration of the plurality of metal layer patterns2.

(Metal Layer Pattern)

In one metal layer pattern 2, six pixel openings (openings) 2 a arearranged in a first direction X perpendicular to the laminatingdirection Z, and 480 pixel openings 2 a, for example, are arranged in asecond direction Y perpendicular to the laminating direction Z and thefirst direction X. The first and second directions X and Y are parallelto the main surface 10 a of the first transparent substrate 10. Theplurality of metal layer patterns 2 are arranged in the first directionX, being electrically insulated from each other. The metal layerpatterns 2 are extended in the second direction Y.

For example, a pixel opening 2 a can be made into a polygonal shape,including at least two parallel sides,

As the polygonal shape having two parallel sides, a rectangle, ahexagon, a V-shape (doglegged shape), and the like can be mentioned. Asthe shape of a frame surrounding these polygonal pixels, anelectrically-closed shape can be used. Sensitivity of electrical noisepropagated from periphery of the liquid crystal display device dependson whether the pattern shape is electrically closed or partially open(include portions which appear to be discontinuous) in plan view.Alternatively, Sensitivity of electrical noise propagated from peripheryof the liquid crystal display device depends on the pattern shape or thearea of the metal layer patterns 2.

Each metal layer pattern 2 includes at least one of an alloy layermainly containing copper, and a copper layer. The alloy layer mainlycontaining copper refers to an alloy layer that contains more than 50%by weight of copper. The copper layer refers to a layer formed of purecopper.

When the metal layer pattern 2 is formed of a thin film of an alloylayer, and if the film thickness (thickness, i.e., the length in thelaminating direction Z) is 100 nm (nanometers) or more, or 150 nm ormore, the metal layer pattern 2 hardly transmits visible lighttherethrough. Accordingly, if the thickness of the metal layer pattern 2according to the present embodiment is in the range of approximately 100nm to 200 nm, for example, sufficient light resistance can be obtained.As will be described below, a part of the metal layer pattern 2 can beformed in the laminating direction Z being formed as a metal layercontaining oxygen.

Each metal layer pattern 2 may be configured of a plurality of layers.In this case, at least one of the plurality of layers is an alloy layer.It should be noted that each metal layer pattern 2 may be configured ofa single layer.

If each metal layer pattern 2 has an alloy layer, alloy elementscontained in the alloy layer in addition to copper are preferably one ormore selected from magnesium, calcium, titanium, molybdenum, indium,tin, zinc, aluminum, beryllium, and nickel. With such a configuration,adhesiveness between the metal layer patterns 2 and a glass substrate ora resin (e.g., the light absorptive resin layers) can be enhanced.Copper is a conductor having good alkali resistance and small electricalresistance, but can be insufficient when adhesiveness to glass or aresin is concerned. By alloying copper to form an alloy layer mainlycontaining copper, adhesiveness between the metal layer patterns 2 and aglass substrate or a resin can be improved.

The amount of alloy elements added to copper in the alloy layer ispreferably 3 at % or less, because this amount can prevent significantincrease of the resistance of the alloy layer. If the amount of alloyelements added to copper is 0.2 at % or more, adhesiveness between thethin alloy layer and a glass substrate or the like is improved. Unlessotherwise specified in the description below, the metal forming themetal layer patterns 2 in the embodiments below, as well as in thepresent embodiment, is an alloy layer containing 1 at % magnesium (therest of the metal is copper). The resistance of the alloy layercontaining 1 at % magnesium does not significantly differ from theresistance of a layer made of only copper.

The alloy layer can be formed by vacuum deposition using sputtering, forexample. The alloy elements may be added to copper so as to generate aconcentration gradient in the laminating direction Z of the alloy layer.A center portion of the alloy layer in the laminating direction Z maycontain 99.8 at % or more copper. The concentration gradient may begenerated such that, in the laminating direction Z of the metal layerpattern 2, the amount of alloy elements on a surface contacting thefirst light absorptive resin layer pattern 1, or on a surface oppositeto the surface contacting the first light absorptive resin layer pattern1 (surface contacting the second light absorptive resin layer pattern3), is larger than the amount of the alloy elements in the centerportion of the metal layer pattern 2 in the laminating direction Z.

In the process of forming the alloy layer, oxygen may be introduced toprovide the layer as an oxygen-containing layer. Specifically, oxygenmay be introduced into a contact layer which ranges, for example, fromthe surface of the alloy layer contacting the first light absorptiveresin layer pattern 1, as a starting point, to a point of 2 nm to 20 nmin the laminating direction Z. The amount of oxygen introduced duringthe forming process can be 10%, for example, relative to the amount of abase gas, such as argon, to be introduced. By containing 5 at % or moreoxygen, for example, the contact layer, being included in the metallayer pattern 2, can improve adhesiveness of the metal layer pattern 2.

When the oxygen content in the base gas is 15 at % or more, adhesivenessmay not be improved. The total thickness of the metal layer pattern 2including the contact layer of the alloy layer can be in the range of102 nm to 320 nm, for example. By forming the oxygen-containing contactlayer on the surface of the metal layer pattern 2, reflectance of themetal layer pattern 2 can be decreased, and low reflection effectsexerted as the black electrode 4 can be enhanced.

It should be noted that nickel, in the form of a copper-nickel alloycontaining 4 at % or more nickel, can be applied to the embodiments ofthe present invention. For example, a copper-nickel alloy containing 4at % or more nickel is formed, first, with a thickness in the range of 5nm to 20 nm, with 5 at % or more oxygen being contained therein bydesign. Further, a copper-nickel alloy containing substantially nooxygen is laminated with a thickness in the range of approximately 100nm to 300 nm to thereby form an electrode for touch sensing having areflectance of 30% or less.

By allowing the copper-nickel alloy to contain 5 at % or more oxygen,the light reflected from the surface of the copper-nickel alloy becomesblack. By providing the first light absorptive resin layer pattern 1 toa boundary surface between the first transparent substrate 10 and themetal layer pattern 2 made of the copper-nickel alloy, reflectance ofthe black electrode 4 can be reduced to 2% or less.

In the liquid crystal display device substrate 22, when viewed from thedisplay area's side, i.e. from the first transparent substrate 10, theblack electrodes 4 serves as a low-reflection black matrix.

In the configuration of the embodiment of the present invention, themetal layer patterns 2 are formed into a frame shape dividing individualpixels, or into a matrix pattern, using a thin line. Therefore, theelectrostatic capacitance (fringe capacitance, see FIG. 12) at an edgeof each metal layer pattern 2 can be increased. In this case, thetransparent electrode patterns 6 each being formed in a large-widthstripe shape and perpendicular to the metal layer patterns 2 can have aconstant electrical potential. The constant electrical potentialincludes 0 (zero) volt, an electrical potential when the transparentelectrode patterns 6 are grounded via a resistor having high resistance,or a constant electrical potential being offset in either a positive ora negative side. A detection driving voltage of a rectangular wave or analternating voltage is applied between the transparent electrodepatterns 6, which are at a constant electrical potential, and the metallayer patterns 2, to detect a fringe capacitance (change in fringecapacitance) per metal layer pattern 2. As shown in a schematic diagramof FIG. 13, with a touch by a pointer P such as a finger, the producedfringe capacitance (electrostatic capacitance produced at the fringeportion) is significantly decreased. In other words, by subtracting theelectrostatic capacitance after the touch by a finger or the like, fromthe electrostatic capacitance before the touch (detecting a change), alarge difference in fringe capacitance (change in electrostaticcapacitance) can be obtained to improve and even significantly improvethe S/N ratio in touch sensing. In the present invention, the change inthe detected fringe capacitance is larger, and hence the driving voltagecan be set to a small value, for example, to make the influence of astray capacitance smaller than when the driving voltage is set to alarge value.

When applying offset to an alternating voltage or a voltage of arectangular wave (bias voltage is applied), the constant electricalpotential can be set to a median voltage of the alternating voltage orthe like. The constant electrical potential is thus not limited to 0(zero) volt. By setting the driving voltage to a small value, powerconsumption can be reduced.

For example, two types of metal layer patterns 2 (black electrodes 4)can be used to calculate (carry out subtraction for) an electrostaticcapacitance in touch sensing, for noise compensation. For example, thetwo types of metal layer patterns 2 are obtained by providing differentfringe lengths, with the areas thereof being made equal. By obtaining adifference in fringe capacitance across the two types of the metal layerpatterns 2 by subtraction, noise produced at the metal layer patterns 2can be cancelled. The area of each metal layer pattern 2 can be adjustedby designing the shape of a bezel portion (frame portion) outside thedisplay unit or the like, for example. The size and shape of each metallayer pattern 2 can be adjusted to reduce the influence of aninterference noise entering the liquid crystal display device fromoutside (hereinafter referred to as external noise). A part of the metallayer patterns 2 may be open (may include portions discontinuous in planview). The driving frequency for touch sensing is preferably differentfrom an average frequency of the main external noise.

For example, in contrast to the embodiment of the present invention, inthe structure of the two sets of touch electrodes which are adjacentlyflush with each other as shown in FIG. 11 of PTL 4 mentioned above, itis difficult to obtain a large difference in fringe capacitance or achange in electrostatic capacitance before and after touch sensing, andis also difficult to use stylus input for high definition pixels.

As shown in FIG. 3, each metal layer pattern 2 is defined, for example,to include six pixel openings 2 a as a unit in the first direction X.The metal layer patterns 2 are arranged in the first direction X, bypatterning, so as to be electrically insulated from each other, i.e.electrically independent of each other. A spacing 15 that is a gap isformed between the metal layer patterns 2 adjacent in the firstdirection X.

An array of 320 metal layer patterns 2 in the first direction X, forexample, can provide 1920×480 pixels on the liquid crystal displaydevice substrate 22. The pixel unit to be divided can be adjusted inconformity with the accuracy of touch sensing or the purpose of use.

Each metal layer pattern 2 can be used as a detection electrode thatdetects a change in electrostatic capacitance generated in touchsensing, or a driving electrode of touch sensing (touch drivingelectrode). The following description will be focused on the case wherethe metal layer pattern 2 is mainly used as a driving electrode.

The plurality of first light absorptive resin layer patterns 1, theplurality of second light absorptive resin layer patterns 3, and theplurality of black electrodes 4 also have pixel openings (openings) la,pixel openings (openings) 3 a, and pixel openings 4 a formed therein,respectively, as in the metal layer patterns 2. The spacing 15 is formedbetween the first light absorptive resin layer patterns 1, between thesecond light absorptive resin layer patterns 3, and between the blackelectrodes 4, adjacent in the first direction X. The first lightabsorptive resin layer patterns 1, the second light absorptive resinlayer patterns 3, and the black electrodes 4, adjacent in the firstdirection X, are electrically insulated from each other.

In the pixel openings 4 a, the pixel openings 1 a, the pixel openings 2a, and the pixel openings 3 a are aligned in the laminating direction Z.

As shown in FIG. 2, the plurality of black electrodes 4 are disposed ata boundary surface between the first transparent substrate 10 and thetransparent resin layer 5.

(Light Absorptive Resin Layer Pattern)

The first light absorptive resin layer patterns 1 and the second lightabsorptive resin layer patterns 3 are electrical insulators, forexample. Main light absorptive black color materials that can becontained in the light absorptive resin layer patterns 1 and 3 includecarbon, carbon nanotubes (hereinafter referred to as CNT), metalparticulates, and the like. The concentration of carbon or CNT may bevaried in the thickness direction of the first light absorptive resinlayer pattern 1. Each first light absorptive resin layer pattern 1 mayhave a two-layer configuration including a light absorbing resin layerthat contains carbon as a main light absorbing material, and a lightabsorptive resin layer that contains CNT as a main light absorbingmaterial. Various organic pigments may be added to the black colormaterial to adjust color. Using carbon as a “main light absorbingmaterial” refers to that the content of carbon relative to the pigmentsin the black color material is 51% or more by weight ratio. The firstlight absorptive resin layer pattern 1 better prevents light from beingreflected to the observer. The observer's eye visually recognizes thefirst light absorptive resin layer pattern 1 as black.

The optical density of the first light absorptive resin layer pattern 1in transmission measurement can be less than 2, for example. Forexample, it is preferable that the optical density of the first lightabsorptive resin layer pattern 1 per 1 μm thickness in transmissionmeasurement is in the range of 0.4 to 1.8, inclusive, and the thicknessof the first light absorptive resin layer pattern 1 is in the range of0.1 μm to 0.8 μm, inclusive. The optical density and the thickness canbe set, as needed, to values outside the numerical ranges mentionedabove. However, the amount of carbon per 1 μm thickness of the firstlight absorptive resin layer pattern 1 is preferably adjusted such thatthe light reflectance at the boundary surface between the firsttransparent substrate 10 and the light absorptive resin layer pattern 1is less than 2%.

If the light reflectance at the boundary surface exceeds 2%, the blackcolor on a display screen of the normally-black liquid crystal displaydevice becomes more visually different from the color of the frame(bezel) (usually black). From a design viewpoint, the color of the blackcolor material or the amount of carbon is desirably adjusted such thatthe light reflectance at the boundary surface between the firsttransparent substrate 10 and the first light absorptive resin layerpattern 1 is less than 2%. Further, the concentration of the black colormaterial may be varied in the thickness direction of the lightabsorptive resin layer, or the light absorptive resin layer may beformed of a plurality of layers with different concentrations of theblack color material. Further, the light absorptive resin layer may beformed of a plurality of layers made of resins having differentrefractive indices. It is desirable that the resins used for the lightabsorptive resin layer have a low refractive index.

The optical density or the hue of the first light absorptive resin layerpattern 1 can be adjusted by the amount of the black color material,such as carbon, or the amount of several organic pigments added tocarbon. By decreasing the amount of carbon contained in the first lightabsorptive resin layer pattern 1 within a range of not increasing lightreflected from the metal layer pattern 2, reflected light at theboundary surface between the first transparent substrate 10 and thefirst light absorptive resin layer pattern 1 can be decreased, and thusvisibility is improved.

For example, the second light absorptive resin layer patterns 3 can beobtained by applying a photosensitive black coating liquid onto thefirst transparent substrate 10 where the metal layer has been formed,for exposure and development with a desired pattern, followed by heattreatment or the like for curing. The thickness of the second lightabsorptive resin layer patterns 3 when coated is a little larger than atarget thickness, considering in advance a film loss due to dry etchingdescribed below.

The photosensitive black coating liquid is prepared, for example, bydispersing carbon or the like in a mixture of an organic solvent and aphoto-crosslinkable acrylic resin and an initiator therefor, with orwithout a thermosetting curing agent.

A thermosetting-type black coating liquid can be prepared by adding onlya thermosetting curing agent, without adding a photoinitiator. The blackcolor material mainly containing carbon in the embodiment of the presentinvention refers to a black coating liquid to which carbon is added at aratio exceeding 51 wt %, relative to the total weight of pigments.

In the second light absorptive resin layer patterns 3, the concentrationcan be varied in the thickness direction or a layer configuration can bechanged, as in the first light absorptive resin layer patterns 1.

In the second light absorptive resin layer patterns 3, only the portionscorresponding to terminals 61 are preferably removed in a region C, apart of the terminals 61 shown in FIG. 4, for example. Removalassociated with the second light absorptive resin layer patterns 3 forthe terminals 61 is achieved by dry etching, together with thetransparent resin layer 5. This can further be followed by laminatingthe transparent electrode pattern 6 (conductive film such as of ITO) toprovide a terminal cover.

The thickness of the black electrode 4 is desirably small. The thicknessof the black electrode 4 corresponds to the total thickness of the threelayers of the first light absorptive resin layer pattern 1, the metallayer pattern 2, and the second light absorptive resin layer pattern 3.If the thickness of the black electrode 4 is small, unevenness orprotrusions on the surface thereof can be made small, to therebyminimize poor alignment and the like of the liquid crystal, for example.For example, the first light absorptive resin layer pattern 1 can have athickness of 700 nm, the metal layer pattern 2 can have a thickness of180 nm, and the second light absorptive resin layer pattern 3 can have athickness of 400 nm. The total thickness of the black electrode 4 inthis case is 1280 nm (1.28 μm). If the black electrode 4 has a smallthickness, a color filter obtained by laminating colored layers such asred, green, and blue layers, as described below, is likely to be flat.

Since the black electrode 4 according to the present invention uses, inits configuration, the metal layer pattern 2 having higher lightshielding properties, the thickness or the optical density of the lightabsorptive resin layer can be decreased. In this way, if the lightabsorptive resin layer is formed with a small thickness, or has a lowoptical density, resolution in photolithography is improved. Thus, forexample, the black electrode 4 can be formed of a thin line having aline width in the range of 1 μm to 4 μm.

(Potential Role of Black Electrode and Transparent Electrode)

The black electrode described above can serve as a driving electrode(scanning electrode) of the liquid crystal display device 100 in touchsensing, for example. If the black electrode is taken to be a drivingelectrode in touch sensing, and the transparent electrode pattern 6 istaken to be a detection electrode, a driving condition of touch sensingcan be made different from a driving condition of the liquid crystal(frequency, voltage, etc.). By making the driving frequency of touchsensing different from the driving frequency of the liquid crystal, theinfluence of touch sensing driving on liquid crystal driving, or viceversa, can be reduced. For example, the driving frequency of touchsensing can be set to several KHz to several tens of KHz, and thefrequency of liquid crystal driving can be set to a range of 60 Hz to240 Hz. Further, the touch sensing driving and the liquid crystaldriving can also be performed in a time-division manner.

In the case of using each black electrode as a driving electrode(scanning electrode), the scanning frequency in detecting anelectrostatic capacitance can be arbitrarily adjusted in conformity witha requested touch input speed. Further, to obtain quick responsiveness,black electrodes selected from all of the black electrodes (the numberof the selected black electrodes is smaller than that of the entireblack electrodes) can be scanned (thinned-out scanning), instead ofscanning all of the plurality of black electrodes.

Alternatively, the black electrode can serve as a driving electrode(scanning electrode) to which a voltage at a constant frequency isapplied. The voltage (alternating-current signal) applied to thescanning electrode may be based on an inversion driving method in whichpositive and negative voltage are inverted.

Alternatively, amplitude of the voltage (width of high and low voltages,peak-to-peak) of the alternating-current signal, as a touch drivingvoltage, to be applied can be decreased to thereby mitigate theinfluence on the liquid crystal display. The role of the scanningelectrode and the role of the detection electrode may be switched.

The black electrodes sandwiching the metal layer pattern have a smallresistance. The transparent electrode pattern 6 can also be permitted tohave a small resistance, by being provided with an auxiliary conductoror the like, for example. With such low resistances, a change inelectrostatic capacitance generated in touch sensing can be detectedwith higher accuracy. Black electrodes including a copper alloy film,that is a good conductor, can be arranged in a matrix pattern using athin line with a width of 1 to 4 μm, for example, having a lowresistance.

Due to the fringe effect of the black electrode pattern having a smallline width arranged above the transparent electrode pattern 6, theelectrostatic capacitance (fringe capacitance) in the vicinity of thepattern edge is increased, while the electrostatic capacitance can beincreased. In other words, the difference in electrostatic capacitancebetween presence and absence of a touch by a pointer such as a fingercan be increased, and the S/N ratio relating to touch sensing of theliquid crystal display device 100 can be increased, leading to highdetection accuracy.

When viewed from a display area of the display unit 110, for example,the black electrodes serve as a black matrix with a low reflection andthus can improve visibility. By adjusting the concentration of the blackcolor material contained in the first light absorptive resin layerpattern 1, and also adjusting the thickness of each light absorptiveresin layer, and the refractive index of a resin contained in each lightabsorptive resin layer, reflectance of light generated at the boundarysurface between the first transparent substrate 10 and the first lightabsorptive resin layer pattern 1 can be reduced. In addition, if themetal layer pattern 2 used in each black electrode is thin, it cancompletely shield visible light, and eliminate light leakage from thebacklight.

Further, the black electrodes of the embodiment of the present inventionare obtained by dry-etching the light absorptive resin layer patterns 1and 3, using the metal layer or the second light absorptive resin layeras a matrix (mask). Thus, the black electrodes are characterized in thatthe drawn line width or shape of the light absorptive resin layerpatterns 1 and 3 is substantially the same as that of the metal layerpatterns 2.

Since the drawn line width of the light absorptive resin layer patterns1 and 3 is substantially the same as that of the metal layer patterns 2,the aperture ratio of the pixels will not be lowered. Since the lightabsorptive resin layer patterns 1 and 3, and the metal layer patterns 2can be formed by dry etching, these patterns can be formed with asmaller line width than in other forming methods. For example, thesepatterns can be formed with a line which is as thin as a metal wiringused for TFTs (thin film transistors).

The transparent resin layer 5 can be formed of an acrylic resin or thelike having thermosetting properties. In this example, the transparentresin layer 5 has a thickness of 1.5 The thickness of the transparentresin layer 5 can be determined as desired as long as the metal layerpattern 2 is electrically insulated from the transparent electrodepattern 6. The first light absorptive resin layer pattern 1 or thetransparent resin layer 5 described above may adopt a configuration inwhich a plurality of layers having different optical properties such asa refractive index are laminated, for example.

As shown in FIGS. 2 and 4, the plurality of transparent electrodepatterns 6 are arranged on the transparent resin layer 5 so as to beinsulated from each other, i.e. electrically independent of each other,in the second direction Y, for example. The transparent electrodepatterns 6 is formed on the transparent resin layer 5 into a stripeshape extending in the first direction X perpendicular to the metallayer pattern 2.

In the liquid crystal display device with a high definition of 300 ppior more, for example, when viewed in the laminating direction Zindicated in FIG. 4, each transparent electrode pattern 6 preferablyoverlaps three or more pixel openings 2 a of the metal layer patterns 2in the second direction Y. The number of the pixel openings 2 a withwhich each transparent electrode pattern 6 overlaps in the seconddirection Y does not necessarily have to be three, but may be six, nine,or the like.

With such a configuration, three or more pixel openings 2 a arecollectively scanned in the second direction Y, and hence the timerequired for scanning the entire display unit 110 can be reduced.

The transparent electrode patterns 6 are formed of a conductive metaloxide referred to as ITO, and the thickness of the transparent electrodepatterns 6 is, but is not limited to, 140 nm in this example. Eachtransparent electrode pattern 6 serves as another touch electrode to bepaired with a corresponding metal layer pattern 2.

To decrease a resistance as described below, each transparent electrodepattern 6 can be provided with a thin line that is a metal filmextending in the longitudinal direction of the pattern (lengthwisedirection of the stripe which is the first direction X), as an auxiliaryconductor.

The transparent electrode pattern 6 can be used as a detection electrodein touch sensing.

In the embodiment of the present invention, both of the black electrodes4 and the transparent electrode patterns 6 associated with touch sensingare provided on a surface of the first transparent substrate 10, thesurface of the first transparent substrate 10 being in contact with theliquid crystal layer 24 (main surface 10 a). If the electrodes 4 or theelectrode patterns 6 are formed on a front surface of the firsttransparent substrate 10 (surface on the opposite side to the mainsurface 10 a), formation of a fringe capacitance across the blackelectrode 4 and the transparent electrode pattern 6 is adverselyaffected, due to the large thickness of the first transparent substrate10. If the fringe capacitance formed is small, the S/N ratio at the timeof touch detection is decreased.

As shown in FIGS. 3 and 4, the plurality of metal layer patterns 2 andthe plurality of transparent electrode patterns 6 can be provided withterminals 61, each serving as an electrode extracting portion. Theseterminals 61 are desirably arranged in a region D for the terminals 61.The region D is located outside a display region that is in arectangular shape in the entirety as defined by the plurality of pixelopenings 4 a.

Not all of the plurality of metal layer patterns 2 need to be used asdriving electrodes for touch signals, and the metal layer patterns 2 canbe driven (scanned) in a thinned-out manner, such as in a manner ofusing every third metal layer pattern 2 in the first direction X(thinning (skipping) two out of three metal layer patterns 2 to scan onemetal layer pattern 2), for example.

The metal layer patterns 2 that are not used as driving electrodes maybe in an electrically-floating form (floating patterns).

When liquid crystal is driven, the transparent electrode patterns 6 canbe set to a common electrical potential, having a constant electricalpotential. Alternatively, all of the transparent electrode patterns 6can be grounded via a resistor having a high resistance.

By increasing the number of metal layer patterns 2 to be thinned todecrease the number of scan lines, the driving frequency can be loweredand power consumption can be reduced. In contrast, by performinghigh-density scanning to ensure improved or even high accuracy and highdefinition, the present invention can be utilized for fingerprintauthentication or the like, for example. The number of scan lines intouch sensing may be adjusted by the control unit. The constantpotential does not necessarily refer to “0 (zero)” volt, but may be anintermediate value between high and low driving voltages. The constantelectrical potential may be set to driving voltage having an offset. Thetransparent electrode patterns 6 have a constant electrical potential,and hence the touch electrodes (black electrodes) may be driven at afrequency different from the driving frequency of the pixel electrodesthat drive the liquid crystal.

Liquid crystal and touch sensing can be driven in a time-divisionmanner. However, since the transparent electrode patterns 6 are at aconstant electrical potential, liquid crystal and touch sensing may bedriven at different frequencies, instead of being driven in atime-division manner. It should be noted that, if the channel layer 46of the thin film transistor 45 is made of an oxide semiconductor such asIGZO (registered trademark), the time-division manner driving can beeasily performed, as will be described below.

As shown in FIGS. 2 and 5, the array substrate 23 has a plurality ofpixel electrodes 25, a plurality of thin film transistors 45, a metalwiring 40, and insulating layers 28 on a main surface (surface) 20 a ofthe second transparent substrate 20, the main surface facing the liquidcrystal layer 24. More specifically, the plurality of pixel electrodes25 and the plurality of thin film transistors 45 are provided on themain surface 20 a of the second transparent substrate 20 via theplurality of insulating layers 28. FIG. 2 does not show the thin filmtransistors 45, and FIG. 5 does not show the insulating layers 28.

The metal wiring 40 has a plurality of signal lines (source lines) 41, aplurality of scan lines (gate lines) 42, and a plurality of auxiliarycapacitance lines 43. Each of the signal lines 41, the scan lines 42 andthe auxiliary capacitance lines 43 have a two-layer configuration madeof titanium and copper. FIG. 18 referred to in a fourth embodimentdescribed below shows the signal line 41 and a light-shielding pattern73.

The pixel electrodes 25 each have a known configuration, and aredisposed on a surface of the insulating layer 28, the surface of theinsulating layer 28 facing the liquid crystal layer 24, so as to facethe pixel openings 4 a of the black electrodes 4.

The metal wiring 40 may be formed of a multilayer configuration having aplurality of layers. In this case, at least one of the plurality oflayers is a copper layer or a copper alloy layer, and other layers caneach be a layer of a metal having a high melting point, such as titaniumor molybdenum. The metal wiring 40 may be configured by laminating ametal having good conductivity, such as copper, on ahorizontally-aligned CNT.

The channel layer 46 in each thin film transistor 45 can be formed of asilicon-based semiconductor such as polysilicon, or an oxidesemiconductor. The channel layer 46 of the thin film transistor 45 ispreferably made of an oxide semiconductor, such as IGZO (registeredtrademark), that contains two or more metal oxides among gallium,indium, zinc, tin, and germanium. Such a thin film transistor 45 hasgood memory effects (having small leak current), and therefore easilyholds a pixel capacitance after application of a liquid crystal drivingvoltage. Accordingly, configuration can be adopted omitting theauxiliary capacitance lines 43.

Thin film transistors that use an oxide semiconductor as a channel layerhave a bottom gate-type structure, for example. A top gate-type, ordouble gate-type transistor structure can also be used for thin filmtransistors. Optical sensors or other active elements can serve as thinfilm transistors that include a channel layer made of an oxidesemiconductor.

The thin film transistor 45 that uses an oxide semiconductor such asIGZO for the channel layer 46 has high electron mobility, and can applya necessary driving voltage in a short time of 2 msec (milliseconds) orless, for example, to the pixel electrode 25. For example, time perframe in double-speed driving (when the number of displayed frames persecond is 120) is about 8.3 msec. In this case, for example, 6 msec canbe allocated to touch sensing. Since the driving electrode, which is thetransparent electrode pattern 6, is at a constant electrical potential,there is no need to perform liquid crystal driving and touch electrodedriving in a time-division manner. The driving frequency of the pixelelectrode for driving the liquid crystal can be different from thedriving frequency of the touch electrode.

The thin film transistor 45 that uses an oxide semiconductor for thechannel layer 46 has small leak current, as mentioned above, and hencecan hold the driving voltage applied to the pixel electrode 25 for along period of time. By forming the signal lines, the scan lines, theauxiliary capacitance lines, or the like of the active elements withcopper wires having a resistance smaller than that of aluminum wires,and using IGZO that can be driven in a short period of time as activeelements, a time margin is extended in scanning in touch sensing, and achange in generated electrostatic capacitance can be accuratelydetected. By applying an oxide semiconductor such as IGZO to the activeelements, the time required for driving the liquid crystal or the likecan be reduced, and sufficient margin can be ensured for the time spentin touch sensing during image signal processing of the entire displayscreen.

A drain electrode 36 extends from the thin film transistor 45 to thecenter of the pixel, and is electrically connected to the pixelelectrode 25, which is a transparent electrode, via a contact hole 44. Asource electrode 35 extends from the thin film transistor 45 and iselectrically connected to the signal line 41.

Liquid crystal molecules of the liquid crystal layer 24 (the alignmentfilm and the liquid crystal molecules are not shown) are used for liquidcrystal driving based on VA method (vertical alignment method:longitudinal electric field method using vertically-aligned liquidcrystal molecules). In the liquid crystal molecules, the initialalignment is a vertical alignment, i.e. in the laminating direction Z,perpendicular to the surfaces of the liquid crystal display devicesubstrate 22 and the array substrate 23.

In each of the embodiments described below, a liquid crystal drivingvoltage is applied across the transparent electrode patterns 6 and thepixel electrodes 25 in the thickness direction of the liquid crystallayer 24, i.e. the laminating direction Z.

In general, the style in which a driving voltage is applied in thethickness direction of the liquid crystal layer is called a longitudinalelectric field method. The liquid crystal layer in the longitudinalelectric field method has a higher front surface transmittance, by about20%, than the liquid crystal layer in horizontal alignment calledtransverse electric field method ((IPS: in plane switching) or FFS(fringe field switching) that is a method in which the liquid crystal isrotated in the horizontal direction). The front surface transmittancerefers to a luminance when the liquid crystal display device is observedfrom a direction normal to the display area (laminating direction Z ofthe present embodiment).

Referring to FIGS. 6 to 8, the reason why the display unit of the liquidcrystal display device based on FFS can have lower transmittance will bebriefly described.

FIG. 6 is a schematic cross-sectional view illustrating a conventionaldisplay unit 200 based on the transverse electric-field driving methodcalled IPS or FFS. The initial alignment of a liquid crystal layer 206is a horizontal alignment parallel to a surface of a transparentsubstrate 207. The liquid crystal layer 206 is driven by a liquidcrystal driving voltage applied across a pixel electrode 208 locatedbelow the liquid crystal layer 206, and a common electrode 210 locatedbelow a pixel electrode 208, via an insulating layer 209. As a result,electric force lines L1 are formed between the pixel electrode 208 andthe common electrode 210.

A transparent resin layer 213, a color filter 214, and a transparentsubstrate 215 are arranged above the liquid crystal layer 206 in thisorder.

An effective thickness R1, which is a part of the liquid crystal layer206 in the thickness direction, mainly influences the transmittance ofthe liquid crystal layer 206. In the longitudinal electric-field drivingmethod mentioned in the embodiments of the present invention,substantially the entire thickness of the liquid crystal layer 24 has aneffect on the transmittance (e.g., see FIG. 2). On the other hand, inthe FFS liquid crystal display method that is a transverseelectric-field driving method, only the effective thickness R1, which isa part of the thickness of the liquid crystal layer 206, has an effecton the transmittance of the liquid crystal layer 206. Accordingly, frontsurface luminance (transmittance) becomes lower in the transverseelectric-field driving method than in the longitudinal electric-fielddriving method.

FIG. 7 is a schematic diagram illustrating equipotential lines L2 when aliquid crystal driving voltage is applied to the display unit 200. Inthe absence of a transparent electrode or a conductive film from thetransparent substrate 215 side, the equipotential lines L2 penetrate thetransparent resin layer 213, the color filter 214, and the transparentsubstrate 215 and extend upward. If the equipotential lines L2 areextended in the thickness direction of the liquid crystal layer 206, theeffective thickness of the liquid crystal layer 206 is ensured to someextent. Therefore, the intrinsic transmittance of the display unit 200based on the transverse electric-field driving method can be betterachieved.

Let us discuss the case where a counter electrode 221 is providedbetween the liquid crystal layer 206 and the transparent resin layer 213in addition to the components of the above-mentioned display unit 200,as in the case of a conventional display unit 200A shown in FIG. 8. Inthis case, since equipotential lines L3 do not penetrate the counterelectrode 221, the shape of the equipotential lines L3 is deformed fromthe shape of the above-mentioned equipotential lines L2.

In this case, the effective thickness of the liquid crystal layer 206becomes smaller than that of the liquid crystal layer 206 in the displayunit 200, which can cause a significant decrease in luminance(transmittance) of the display unit 200A.

Accordingly, it is difficult to apply the touch screen recited in claims1 to 5 of PTL 2 mentioned above to the display unit based on thetransverse electric-field driving method because of the problem oftransmittance. Therefore, the main objective display unit of a touchscreen according to claims 1 to 5 of PTL 2 is estimated to be a liquidcrystal display device based on the longitudinal electric-field drivingmethod. However, PTL 2 fails to describe in detail the liquid crystallayer in longitudinal electric-field driving. PTL 2 fails to study theinfluence of the touch screen configuration on the luminance(transmittance) of the display unit.

The liquid crystal display device 100 will be described again.

Liquid crystal molecules in the liquid crystal layer 24, not shown,exhibit negative dielectric anisotropy. The liquid crystal displaydevice 100 includes polarizing plates, not shown. These polarizingplates, in crossed nicols, are normally black. The gap of the liquidcrystal cells was set to 3.6 μm, although the gap width is not limitedto this.

Liquid crystal molecules, which have been aligned in the laminatingdirection Z as an initial alignment, are inclined in a directionintersecting the laminating direction Z, by a voltage being appliedacross the transparent electrode patterns 6 and the pixel electrodes 25in the laminating direction Z to thereby perform ON display (whitedisplay).

It should be noted that the liquid crystal molecules may exhibitpositive dielectric anisotropy and perform display in a normally-blackmode. In this case, however, horizontal alignment processing is needed.It is convenient to use liquid crystal molecules which exhibit negativedielectric anisotropy and can be vertically aligned with simplealignment processing.

In the alignment processing of the alignment film, optical alignment canbe used.

(Auxiliary Conductor)

To decrease resistance of the electrodes, an auxiliary conductor can beformed on the plurality of transparent electrode patterns 6. Theauxiliary conductor may be formed of the same material as that of themetal layer pattern 2, or may be formed of a thin aluminum alloy film.The aluminum alloy can be obtained by adding an alloy element in therange of 0.2 at % to 3 at % to aluminum. As the alloy element, one ormore can be selected from magnesium, calcium, titanium, indium, tin,zinc, neodymium, nickel, copper, and the like. The resistivity of theauxiliary conductor is preferably smaller than that of the transparentelectrode pattern 6.

In the plan view shown in FIG. 9, an auxiliary conductor 16 may beextended in the first direction X, and formed into a linear pattern(stripe pattern) that passes through a center portion in the seconddirection Y of the pixel openings 4 a. In this case, when viewed in thelaminating direction Z, the auxiliary conductor 16 is desirably formedat a position that overlaps the auxiliary capacitance line 43 of thearray substrate 23, for example. With such a configuration, a decreasein aperture ratio can be minimized.

In the plan view shown in FIG. 10, the auxiliary conductor 16 may beformed at a position of the touch electrode pattern made up of the lightabsorptive resin layer patterns 1 and 3 and the metal layer pattern 2,i.e. at a position of the black matrix. The metal wiring 40 forming thesignal lines (the source lines) 41, the scan lines (the gate lines) 42,and the auxiliary capacitance lines 43 of the array substrate 23 istypically disposed in a lower portion of the black matrix (a position inthe black matrix nearer to the second transparent substrate 20 than tothe first transparent substrate 10). Accordingly, by forming theauxiliary conductor 16 at a position where the metal wiring 40 isdisposed, the auxiliary conductor 16 overlaps the metal wiring 40 whenviewed in the laminating direction Z and minimizes decrease in apertureratio.

In the present embodiment, when touch sensing is performed, thetransparent electrode pattern 6 is used as a detection electrode oftouch sensing and, when liquid crystal is driven, used as a commonelectrode to which a voltage is applied to drive the liquid crystalbetween the pixel electrode 25 and the transparent electrode pattern 6,for example. Touch sensing and liquid crystal driving may be performedat different time points in a time-division manner, or may be performedat different frequencies.

As shown in FIG. 1, the control unit 120 has a known configuration, andincludes an image signal timing controller 121 (first control unit), atouch sensing and scan signal controller 122 (second control unit), anda system controller 123 (third control unit).

The image signal timing controller 121 sets the plurality of transparentelectrode patterns 6 to a constant electrical potential, and transmits asignal to the signal lines 41 and the scan lines 42 of the arraysubstrate 23. The image signal timing controller 121 applies a liquidcrystal driving voltage for displaying, to the pixel electrode 25 in thelaminating direction Z, across the transparent electrode patterns 6 andthe pixel electrodes 25, to thereby perform liquid crystal driving, withwhich liquid crystal molecules in the liquid crystal layer 24 aredriven. Thus, an image is displayed on the array substrate 23.

The touch sensing/scan signal controller 122 sets the plurality oftransparent electrode patterns 6 to a constant electrical potential,applies a detection driving voltage to the plurality of metal layerpatterns 2 (black electrodes 4), and detects a change in electrostaticcapacitance (fringe capacitance) across the metal layer patterns 2 andthe transparent electrode patterns 6 to perform touch sensing.

The system controller 123 controls the image signal timing controller121 and the touch sensing/scan signal controller 122, and canalternately perform liquid crystal driving and detection of a change inelectrostatic capacitance, i.e. in a time-division manner.

(Example of Manufacturing Method for Liquid Crystal Display DeviceSubstrate)

Next, a method of manufacturing the liquid crystal display devicesubstrate 22 of the display unit 110 configured as described above willbe described. FIG. 11 is a flowchart illustrating a method ofmanufacturing the liquid crystal display device substrate 22.

In forming a first coating of a light absorptive resin layer (step S11),the above-described black coating liquid having thermosetting propertieswas used. The first light absorptive resin layer is a resin layer beforeshape of the light absorptive resin layer pattern 1 is patterned. Afterheat treatment at 250° C., the light absorptive resin layer had athickness of 0.7 μm. Carbon particulates were used for the black colormaterial.

The first light absorptive resin layer may be formed so as to have athickness other than 0.7 μm. By adjusting the thickness of the firstlight absorptive resin layer and the concentration of the black colormaterial, which is carbon, the light reflection occurring at theboundary surface between the first transparent substrate 10 and thefirst light absorptive resin layer pattern 1 can be adjusted. In otherwords, by adjusting the thickness of the first light absorptive resinlayer pattern 1 and the concentration of the black color materialtherein, the light reflection occurring at the boundary surface can bereduced to 1.8% or less.

The first light absorptive resin layer formed by coating was subjectedto heat treatment at 250° C. to cure the first light absorptive resinlayer.

After first the light absorptive resin layer was cured, a metal layercontaining 1 at % magnesium was formed by means of a sputteringapparatus (step S12). This metal layer is a layer before shape of themetal layer pattern 2 is patterned. At an early stage of the metal layerforming step, a first metal layer containing oxygen with a thickness of0.01 μm was formed under a gas condition in which 10 vol % oxygen gaswas added to an argon gas base, followed by forming a second metal layerwith a thickness of 0.17 μm only by the argon gas base, therebyobtaining a metal layer having a total thickness of 0.18 μm.

Next, a second light absorptive resin layer was formed by coating, usinga black coating liquid obtained by dispersing an alkali developablephotosensitive resin and a black color material, which was carbon, in anorganic solvent (step S13). After being dried at 80° C., the secondlight absorptive resin layer was exposed and developed into a patternshape of the black electrode, further followed by heat treatment at 250°C., thereby obtaining a black pattern with a thickness of 1.1 μm. Aswill be described below, the black pattern finally becomes the secondlight absorptive resin layer pattern 3 through dry etching (step S16)described below.

The black pattern was wet-etched to form the second light absorptiveresin layer pattern 3 (step S14).

The metal layer was wet-etched to obtain the metal layer pattern 2 inwhich the pixel openings 2 a were formed (step S15).

Next, using oxygen and a fluorocarbon gas as an introduction gas,anisotropic dry etching was performed by means of a dry etchingapparatus (step S16). Through dry etching, the first light absorptiveresin layer was approximately vertically processed in the thicknessdirection until the surface of the first transparent substrate 10 wasexposed, such that the line width and the shape were equal to those ofthe metal layer pattern 2 in plan view. In this processing, the firstlight absorptive resin layer pattern 1 was formed from the first lightabsorptive resin layer.

In this case, due to dry etching, the thickness of the second lightabsorptive resin layer pattern 3 on the metal layer pattern 2 wasreduced. The second light absorptive resin layer pattern 3 was left as athin film with a thickness of 0.4 μm.

Washing and drying was performed to form the metal layer pattern 2,followed by coating an alkali soluble photosensitive acrylic resin ontothe metal layer pattern 2, thereby forming the transparent resin layer 5with a thickness of 1.6 μm (step S17). The transparent resin layer 5 wasformed only in the display region, and the periphery of the displayregion was removed by development to expose the region of the terminals61 made of the metal layer pattern 2.

After forming the transparent resin layer 5, a transparent conductivefilm called ITO was formed on the transparent resin layer 5 by means ofa sputtering apparatus (step S18). The transparent conductive film wasformed into the transparent electrode patterns 6 using a well-knownphotolithography technique (step S19). The transparent electrodepatterns 6 and the metal layer patterns 2 are arrays of patterns thatare electrically isolated from each other, and are arrayed via thetransparent resin layer 5 in directions perpendicular to each other. Inthe region of the terminals 61, a transparent conductive film (film of atransparent electrode), which is ITO, is also laminated.

The resin used for the first light absorptive resin layer preferably hasa low refractive index. By adjusting the refractive index of the resin,the content of the black color material such as carbon, and thethickness of the first light absorptive resin layer pattern 1,reflectance of light reflected from the boundary surface between thefirst transparent substrate 10 and the first light absorptive resinlayer pattern 1 can be decreased to 1.8% or less, when viewed from thefirst transparent substrate 10.

However, since there is a limit in the refractive index of the resin,the lower limit of the reflectance of light reflected from the boundarysurface is 0.2%. In the case where the solid content of the resin, suchas an acrylic resin, of the black coating liquid is 14 mass %, forexample, if the amount of carbon in the black coating liquid is withinthe range of about 6 mass % to about 25 mass %, the optical density ofthe first light absorptive resin layer pattern 1 per 1 μm thickness canbe 0.4 to 1.8.

If the first light absorptive resin layer pattern 1 has a thickness of0.3 μm, the effective optical density is in the range of 0.12 to 0.54.If the first light absorptive resin layer pattern 1 has a thickness of0.7 μm, the effective optical density is within the range from 0.28 to1.26.

The liquid crystal display device substrate 22 of the display unit 110is configured by laminating the plurality of first light absorptiveresin layer patterns 1, the plurality of metal layer patterns 2, theplurality of second light absorptive resin layer patterns 3, thetransparent resin layer 5, and the plurality of transparent electrodepatterns 6 in this order on the main surface 10 a of the firsttransparent substrate 10.

In the display unit 110 configured in this way, retroreflection ordiffused reflection of light in the liquid crystal cell, for example, isreduced by the second light absorptive resin layer patterns 3. Forexample, the light emitted from a backlight, not shown, and incidentfrom the second transparent substrate 20 is prevented from beingretroreflected at a surface of each metal layer pattern 2, and lightincident on an active element such as TFT is reduced. In addition, areddish reflection color of the copper alloy can be prevented fromadversely affecting liquid crystal display.

The liquid crystal display device substrate 22 is manufactured with theprocedure described above.

(Effect of Touch Electrode)

The following description addresses an effect of the touch electrode inthe display unit 110, in particular, configured as described above.

According to the display unit 110, each transparent electrode pattern 6can be used as a detection electrode in touch sensing, and each blackelectrode 4 can be used as a scanning electrode to which a voltage isapplied at a constant frequency.

Specifically, as shown in FIG. 12, an electrostatic capacitance fortouch sensing is generated between the black electrode 4 and thetransparent electrode pattern 6. In a normal state, a detection drivingvoltage at a constant frequency is applied across the black electrode 4and the transparent electrode pattern 6, and a fringe electric field isformed in the vicinity of the black electrode 4.

As shown in FIG. 13, if the pointer P such as a finger approaches orcontacts a display screen of the black electrodes 4, for example, thedistribution of the electric force lines L6 is distorted, and anelectrostatic capacitance is soaked into the pointer P, decreasingelectrostatic capacitance across the black electrodes 4 and thetransparent electrode patterns 6. Whether there is a touch by thepointer P is sensed by such a change in electrostatic capacitance. Sincethe spacing between the adjacent black electrodes 4 is small in general,the pointer P simultaneously acts on a plurality of touch electrodes.

Each black electrode 4 according to the present embodiment includes themetal layer pattern 2 formed of at least one of an alloy layercontaining copper having a small resistance as a main material, and acopper layer. The black electrode 4 can be used as a scanning electrodein touch sensing. Each transparent electrode pattern 6 according to thepresent embodiment can have a large pattern width so as to decreaseresistance of the electrode, and can include thereon the auxiliaryconductor 16 to decrease resistance of the electrode. Therefore, the twosets of electrode groups in the capacitive method of the presentembodiment can significantly reduce a time constant associated therewithand significantly improve detection accuracy in touch sensing.

As described above, according to the liquid crystal display device 100of the present embodiment, the plurality of first light absorptive resinlayer patterns 1, the plurality of metal layer patterns 2, and theplurality of the second light absorptive resin layer patterns 3 areformed into the same shape and in alignment when viewed in thelaminating direction Z. Accordingly, the area of each of the pixelopenings 1 a, the pixel openings 2 a, and the pixel opening portions 3 aformed in the laminating direction Z can be enlarged, and the apertureratio can be improved.

The first light absorptive resin layer patterns 1 are provided on theperimeter of each pixel, and hence the perimeter of the pixel can berecognized as being black. Thus, display contrast is improved to therebyenhance visibility.

The pixel electrodes 25 are absent from between the adjacent blackelectrodes 4 of the liquid crystal display device substrate 22.Accordingly, the electrostatic capacitance of the touch electrode can beincreased and the accuracy in detecting the position of the pointer Pcan be enhanced.

The transparent electrode patterns 6 are used in common by the blackelectrodes 4 and the pixel electrodes 25. Accordingly, the number ofelectrodes included in the display unit 110 can be reduced to simplifythe configuration of the display unit 110.

The driving frequency, or the timing of driving or signal detection forthe black electrode as a touch electrode can be set without relying onthe driving frequency or the timing of the liquid crystal.

When liquid crystal display is off, or is black, a driving voltage forthe black electrode is supplied to not all the frames of electrodedriving in each touch sensing, but is applied, one time, to a pluralityof thinned-out frames to detect a touch position, thereby reducing powerconsumption of the liquid crystal display device 100.

For example, the driving frequency for the touch electrode can be higherthan the frequency for liquid crystal driving.

In the present embodiment, the black electrodes 4, i.e. the metal layerpatterns 2 extend in the second direction Y, and the transparentelectrode patterns 6 extend in the first direction X. However, thepresent embodiment may be configured such that the black electrodes 4extend in the first direction X and the transparent electrode patterns 6extend in the second direction Y.

The liquid crystal display device of the present includes, for example,a backlight unit made up of three color LEDs emitting red, green andblue light, for example, and uses a field sequential technique thatsynchronizes the three-color light emissions with liquid crystal displayto thereby realize color display.

If a white LED including three wavelength components of emitting red,green and blue light is used, a liquid crystal display device substrateincluding a color filter as in the subsequent embodiment, for example,can be used to achieve color display.

Second Embodiment

Referring now to FIGS. 14 to 17, a second embodiment of the presentinvention will be described. Those components which are identical withthose of the foregoing embodiment are given the same reference signs toomit duplicate description and to provide description focusing ondifferences.

As shown in FIG. 14, a display unit 111 of the present embodimentincludes a liquid crystal display device substrate 22A, in place of theliquid crystal display device substrate 22 of the display unit 110 ofthe first embodiment. The liquid crystal display device substrate 22A isconfigured such that the pixel opening 4 a of each black electrode 4 ofthe liquid crystal display device substrate 22 is provided with any of ared pixel R formed of a red layer, a green pixel G formed of a greenlayer, and a blue pixel B formed of a blue layer. The red pixel R, greenpixel G, and blue pixel B are each inserted between the metal layerpattern 2 and the transparent resin layer 5 in the laminating directionZ, and disposed adjacently to each other when viewed in the laminatingdirection Z. The liquid crystal layer 24 is a vertically-aligned liquidcrystal as in the first embodiment.

In other words, the display unit 111 includes white LED elements thatinclude red, green, and blue light-emitting components, as a backlight,and are provided with red, green and blue color filters to therebyperform color display.

FIG. 15 is a plan view of the display unit 111 as viewed from above thefirst transparent substrate 10. The pixel openings 4 a provided with anyof the red, green and blue pixels R, G and B are arranged without a gap.

As shown in FIG. 16, the red, green and blue pixels R, G and B arearranged as color filters without a gap on the first transparentsubstrate 10 and on the black electrodes 4. Each of the red, green andblue pixels R, G and B is formed by a well-known photolithographytechnique, by dispersing several organic pigments in a transparentresin, such as an acrylic resin.

The transparent resin layer 5 is laminated on the color filters. Thetransparent electrode patterns 6 are further laminated on thetransparent resin layer 5. The transparent electrode patterns 6 can beformed of a transparent conductive film such as of a conductive metaloxide called ITO, for example, and can be patterned by a well-knownphotolithography technique.

In the present embodiment, when touch sensing is performed, i.e. whendetecting a change in electrostatic capacitance, the transparentelectrode pattern 6 is used as a detection electrode in touch sensing,and, when driving liquid crystal, used as a common electrode to which avoltage is applied to drive the liquid crystal between the commonelectrode and the pixel electrode 25, for example. Liquid crystaldriving is alternated with detection of a change in electrostaticcapacitance. In other words, detection is performed at different timepoints in a time-division manner.

In place of the source signals supplied from the plurality of signallines, positive-polarity signals and negative-polarity signals can bealternately inputted to odd-numbered rows and even-numbered rows, forexample, to perform dot inversion driving of adjacent pixels.

Alternatively, the transparent electrode pattern 6 can serve as adriving electrode (scanning electrode) to perform common electrodeinversion driving in which a positive polarity and a negative polarityare inverted.

As shown in FIG. 17, a set of first light absorptive resin layer pattern1 and the metal layer pattern 2, and the second light absorptive resinlayer pattern 3, each forming part of the black electrode 4, iselectrically isolated due to the spacing 15. A color overlay portion 26of the color filters is disposed on the spacing 15, where two colors areoverlaid to minimize transmission of light emitted from the backlightunit. In the color overlay portion 26, the red and blue pixels R and Bare preferably overlaid.

Although not shown, at a position where the spacing 15 is provided,there is arranged any of the signal line (source line) 41, the scan line(gate line) 42, and the auxiliary capacitance line 43 provided to thearray substrate 23, or a metal wiring pattern similar to these lines, soas to fill the spacing 15 in plan view. This arrangement can contributeto eliminating light leakage from the backlight unit.

The display unit 111 configured in this way can be manufactured usingthe method of manufacturing the liquid crystal display device substrateof the first embodiment, by inserting the red, green and blue pixels R,G and B between the metal layer patterns 2 and the transparent resinlayer 5 through the plurality of pixel openings 4 a, after forming themetal layer patterns 2.

In this case, in the flowchart shown in FIG. 11, a step of forming acolor filter (R, G, B) is inserted between the step S16 of dry etchingthe first light absorptive resin layer pattern and the step S17 offorming the transparent resin layer by coating.

Third Embodiment

The following description addresses a third embodiment of the presentinvention. Those components which are identical with those of theforegoing embodiments are given the same reference signs to omitduplicate description and to provide description focusing ondifferences.

The present embodiment is similar to the first embodiment except for theconfiguration of the metal layer patterns 2, i.e., the configuration ofthe black electrodes 4. Therefore, FIG. 2 is incorporated by reference.However, duplicate description is omitted, and the metal layer pattern 2having differences will be described. The black electrodes 4 of thepresent embodiment can be used as the black electrodes of the secondembodiment described above and a fourth embodiment which will bedescribed below.

In the present embodiment, the metal layer patterns 2 shown in FIG. 2are each formed of a layer having a total thickness of 0.21 μm. Thislayer is obtained by laminating two layers, namely, a first metal layer(layer) made of a copper alloy containing oxygen and having a thicknessof 0.015 μm, and a second metal layer (layer) made of a copper alloycontaining substantially no oxygen and having a thickness of 0.18 μm,and further laminating, on the two layers, a copper-indium alloy layerthat is a copper alloy layer made of copper and indium and having athickness of 0.015 μm. Specifically, each metal layer pattern 2 isconfigured of a plurality of layers, and of the plurality of layers, thelayer nearest to the second transparent substrate 20 is thecopper-indium alloy layer.

Containing substantially no oxygen refers to introducing no oxygen gasin forming the copper alloy film. The copper alloy containing oxygenrefers to that, when a film of this portion is formed, a 10 at % oxygengas is introduced into an argon-based gas, for example, for filmformation.

As the two metal layers formed in advance (first and second metallayers), a copper alloy containing 0.5 at % magnesium and 0.5 at %aluminum (the rest is copper) was used.

The copper-indium alloy layer was made of a copper alloy containing 78at % copper and 22 at % indium.

It should be noted that a minute amount of inevitable impurity iscontained in these copper alloys. The amount of indium to be added tothe copper alloys can be in the range of 0.5 at % to 40 at %. Indium hasa low melting point. There is a concern that a copper alloy, to whichindium has been added at an amount exceeding 50 at %, raises a problemrelating to heat resistance.

The copper alloy film including an indium-rich copper-indium alloylayer, such as one containing 22 at % indium, forms indium oxide priorto forming copper oxide, due to the heat treatment step after filmformation or aging, and minimizes formation of copper oxide. Indiumoxide, which can be a good electrically conductive film, hardly suffersfrom loss of electrical contact. If the amount of copper oxide formed issmall, electrical connection is easily established between a coverterminal and the transparent conductive film, and reliability in themanufacturing process or in mounting can be improved.

A surface of the copper-indium alloy layer achieves a near-whitereflection color, and thus reddening caused by copper as a simplesubstance can be avoided. The reflection color can be neutralized byadjusting not only the ratio of indium to be added, but also the ratioof alloy elements to be added, as exemplified above. The techniquerelating to these copper alloys disclosed in the embodiment of thepresent invention can be applied to the metal wiring 40 of the arraysubstrate 23.

The indium-rich copper-indium alloy contains 10 to 40 at % indium. Bymaking the copper-indium alloy rich, formation of copper oxide isminimized on a surface section, thereby easily establishing electricalcontact as described above.

For example, in a two-layer configuration copper alloy film made up of acopper-titanium alloy as a surface layer, and a dilute alloy (copperalloy containing 3 at % or less alloy elements) as an inner copperalloy, if the content of titanium relative to copper exceeds 10 at %,the etching rate in conducting wet etching is decreased. In this case,the low-etching rate leads to an etching failure of causing the copperalloy film in the titanium-rich surface section to remain in acanopy-like shape.

In the copper-indium alloy, if the amount of the alloy elements is notuniform in the distribution in the thickness direction of the copperalloy film, such an etching failure is unlikely to occur. Thecopper-indium alloy, where the additive amount of indium to the copperalloy is in the range of 0.5 at % to 40 at %, has a heat resistance upto about 500° C., and hence is sufficiently adaptable to an annealingtreatment, at 350° C. to 500° C., of an array substrate including thinfilm transistors using IGZO as a channel layer, for example. The metalwiring 40 of the array substrate 23 can be formed of the copper-indiumalloy.

In the present embodiment, when touch sensing is performed, thetransparent electrode pattern 6 is used as a detection electrode, and,when liquid crystal is driven, used as a common electrode to which avoltage is applied to drive the liquid crystal between the transparentelectrode pattern 6 and the pixel electrode 25. In touch sensing, thedetection electrodes may be set to the same common electrical potential,and may be connected to a conductive casing, for example, so as to beset to a ground electrical potential. Touch sensing driving and liquidcrystal driving can be performed at different timings in a time-divisionmanner.

Fourth Embodiment

With reference to FIGS. 18 and 19, a fourth embodiment of the presentinvention will be described. Those components which are identical withthose of the foregoing embodiments are given the same reference signs toomit duplicate description but to provide description focusing ondifferences.

As shown in FIG. 18, a display unit 112 of the present embodimentincludes a liquid crystal display device substrate 22B including colorfilters (R, G, B), the liquid crystal layer 24, and an array substrate23B.

A concave portion 6 a is formed in a surface of each transparentelectrode pattern 6 of the liquid crystal display device substrate 22Bfacing the second transparent substrate 20. The concave portion 6 a isformed at a position of the transparent electrode pattern 6, theposition overlapping the center portion of the pixel opening 4 a in thefirst direction X, in plan view, i.e. when viewed in the laminatingdirection Z. The concave portion 6 a extends in the second direction Y.The concave portion 6 a can be formed by a well-known photolithographytechnique when the resin material of the transparent resin layer 5 is analkali soluble photosensitive resin, for example. Liquid crystalmolecules 24 a to 24 l in the liquid crystal layer 24 positioned facingthe concave portion 6 a become able to respond at high speed.

The liquid crystal display device substrate 22B has an alignment film 71between the transparent electrode pattern 6 and the liquid crystal layer24.

In plan view, a pixel, a reference sign of which is omitted, isline-symmetrical to a center line M which is parallel to the lateralsides of the pixel opening 2 a formed into a polygonal shape and dividesthe pixel in two parts.

The array substrate 23B includes a pair of pixel electrodes 25 a and 25b replacing the pixel electrode 25 of the array substrate 23 andcorresponding to each pixel, a pair of auxiliary capacitance electrodes56 a and 56 b, and an alignment film 72.

The pixel electrodes 25 a and 25 b as well as the auxiliary capacitanceelectrodes 56 a and 56 b are arranged so as to be line-symmetrical tothe center line M. The auxiliary capacitance electrodes 56 a and 56 bare arranged on a surface of the insulating layer 28 a, the surface ofthe insulating layer 28 a being opposite to the pixel electrodes 25 aand 25 b, the insulating layer 28 a being an insulating layer 28 nearestto the liquid crystal layer 24 among the plurality of the insulatinglayers 28. Specifically, the auxiliary capacitance electrodes 56 a and56 b are formed so as to be located farther from the liquid crystallayer 24 than the pixel electrodes 25 a and 25 b are located, in thelaminating direction Z, via the insulating layer 28 a.

When viewed parallel to the laminating direction Z, an overlap (part) R6of the auxiliary capacitance electrode 56 a overlaps the pixel electrode25 a, but an extension (remaining part) R7 of the auxiliary capacitanceelectrode 56 a does not overlap the pixel electrode 25 a. Similarly,when viewed parallel to the laminating direction Z, an overlap (part) R8of the auxiliary capacitance electrode 56 b overlaps the pixel electrode25 b, but an extension (remaining part) R9 of the auxiliary capacitanceelectrode 56 b does not overlap the pixel electrode 25 b. The extensionsR7 and R9 of the auxiliary capacitance electrodes 56 a and 56 b,respectively, may each have a small length (extension amount) in therange of about 1 μm to about 6 μm, for example, in the first directionX. The extension amount of each of the extensions R7 and R9 isadjustable as appropriate depending on the material of the liquidcrystal, the driving condition, the thickness of the liquid crystallayer 24, and the like.

The auxiliary capacitance electrode 56 a is spaced apart from the centerline M more than the pixel electrode 25 a is. Specifically, theextension R7 of the auxiliary capacitance electrode 56 a is spaced apartfrom the center line M more than the overlap R6 of the auxiliarycapacitance electrode 56 a is.

The auxiliary capacitance electrodes 56 a and 56 b can be set to acommon electrical potential, which is equal to the constant electricalpotential of the transparent electrode pattern 6 included in the liquidcrystal display device substrate 22B, or can be grounded. Alternatively,when a liquid crystal driving voltage is applied to the pixel electrodes25 a and 25 b, the auxiliary capacitance electrodes 56 a and 56 b can beset to an electrical potential different from that of the liquid crystaldriving voltage, or can be set to a reverse potential (with reversedsign).

Since the transparent electrode pattern 6 is at a constant electricalpotential, by applying a different potential to the auxiliarycapacitance electrodes 56 a and 56 b for a short period of time, seizingof the liquid crystal can be prevented, or high-speed response of theliquid crystal can be achieved.

An auxiliary capacitance is formed at the overlap R6 between the pixelelectrode 25 a and the auxiliary capacitance electrode 56 a, and isformed at the overlap R8 between the pixel electrode 25 b and theauxiliary capacitance electrode 56 b.

A light-shielding pattern 73 is provided at a position between theinsulating layers 28 so as to be in alignment with the concave portion 6a, when viewed in the laminating direction Z. The light-shieldingpattern 73 is formed of the same material as that of the signal line 41.

The auxiliary capacitance electrodes 56 a and 56 b and the pixelelectrodes 25 a and 25 b are all formed of a transparent electricallyconductive film such as ITO. The pixel electrodes 25 a and 25 b areelectrically connected to a thin film transistor 45, which is not shown,and a liquid crystal driving voltage is applied to the pixel electrodes25 a and 25 b via the thin film transistor 45.

The liquid crystal molecules 24 a to 24 l in the liquid crystal layer 24exhibit negative dielectric anisotropy. In FIG. 18, the liquid crystalmolecules 24 a to 24 l are shown in an initially aligned state where novoltage is applied to the pixel electrodes 25 a and 25 b.

The alignment films 71 and 72 give a pretilt angle θ to the liquidcrystal molecules such that the liquid crystal molecules 24 a to 24 l istilted relative to the longitudinal direction, from the laminatingdirection Z to a direction in which the auxiliary capacitance electrodes56 a and 56 b are offset from the pixel electrodes (so that end portionsof the liquid crystal molecules are spaced apart from the center line M,the end portions being ones nearer to the first transparent substrate10).

The display unit 112 includes a polarizing plate, a phase differenceplate, and the like, as in typically used display units. Thesecomponents are not shown in FIG. 18.

It should be noted that the display unit 112 may include one to threephase difference plates bonded to a polarizing plate.

The following description of the present embodiment sets forth the casewhere the auxiliary capacitance electrodes 56 a and 56 b are used ascommon electrodes having an electrical potential equal to that of thetransparent electrode patterns 6.

The aligned films 71 and 72 give the pretilt angle θ to the liquidcrystal molecules 24 a to 24 l such that the liquid crystal molecules 24a to 24 l are tilted from the laminating direction Z to a direction inwhich the auxiliary capacitance electrodes 56 a and 56 b extend from thepixel electrodes 25 a and 25 b, and are line-symmetrical to the centerline M. The alignment film 72 is formed at least between the liquidcrystal layer 24 and a surface of each of the pixel electrodes 25 a and25 b.

The display unit 112 of the present embodiment is formed by bonding theliquid crystal display device substrate 22B to the array substrate 23Bvia the liquid crystal layer 24, for example. In alignment processing,the vertically-aligned alignment films 71 and 72 can be irradiated withelectromagnetic waves such as light, while a liquid crystal drivingvoltage (e.g., an alternating-current voltage or direct-current voltageranging from 1 V to 20 V) is applied to the pixel electrodes 25 a and 25b. Through this processing, the liquid crystal molecules 24 a to 24 lcan be imparted with the pretilt angle θ. The light used in thealignment processing may be polarized light, or may be non-polarizedlight.

In the present embodiment, the pretilt angle θ represents an anglerelative to the normal direction of the substrate surface (laminatingdirection Z), when the normal direction is taken to be 0°. The pretiltangle θ can be measured by a crystal rotation method described inJournal of Applied Physics, Vol. 48 No. 5, pp. 1783-1792 (1977), forexample, or other methods.

As shown in FIG. 19, when a liquid crystal driving voltage is applied tothe pixel electrodes 25 a and 25 b, an electric field expressed byelectric force lines L9 is formed from the pixel electrodes 25 a and 25b toward the auxiliary capacitance electrodes 56 a and 56 b (morespecifically, the extensions R7 and R9). Simultaneously, an electricfield expressed by vertical or oblique electric force lines L10 isformed from the pixel electrodes 25 a and 25 b toward the transparentelectrode pattern 6. Conforming to these oblique electric fields, theliquid crystal molecules 24 a to 24 f are inclined in an activationdirection D1 of the first direction X. More specifically, the liquidcrystal molecules 24 a, 24 b, and 24 f are inclined immediately after aliquid crystal driving voltage is applied thereto. Then, immediatelyafter being influenced by the inclined liquid crystal molecules 24 a, 24b, and 24 f, the liquid crystal molecules 24 c to 24 e are inclined inthe activation direction D1.

The liquid crystal molecules 24 g to 24 l are inclined in an activationdirection D2 opposite to the activation direction D1. The liquid crystalmolecules 24 a and 24 l located in an effectively strong electric fieldare activated the earliest, and serve as a trigger for increasing thespeed of liquid crystal display. The liquid crystal molecules 24 b to 24f and 24 g to 24 k in the oblique electric field are also activated athigh speed, similarly to the liquid crystal molecules 24 a and 24 l. Theliquid crystal molecules 24 b to 24 f and 24 g to 24 k are activated inharmonization with the liquid crystal molecules 24 a and 24 l to therebyincrease the speed of liquid crystal display.

By inclining the liquid crystal molecules 24 a to 24 l by an obliqueelectric field as in the present embodiment, the liquid crystalmolecules 24 a to 24 l having the small pretilt angle θ can be driven asif they had an essentially large pretilt angle. Accordingly, with theliquid crystal molecules 24 a to 24 l being inclined by the obliqueelectric field, high-speed liquid crystal display can be realized.

For example, with the liquid crystal molecules 24 a to 24 l beinginclined by the oblique electric field, the liquid crystal molecules 24a to 24 l can be activated at high speed, if the pretilt angle θ issmall as in the range of about 0.1° to about 0.9°. In thevertically-aligned liquid crystal display, the liquid crystal moleculeshaving a large pretilt angle are easily inclined. However, the largepretilt angle tends to cause light leakage during black display as well,and decrease contrast.

In the present embodiment, touch sensing using the black electrodes 4and the transparent electrode patterns 6, as touch electrodes, issimilar to the touch sensing such as in the first embodiment, as far asthe configuration and the driving means are concerned. Therefore,duplicate description is omitted.

The first and fourth embodiments of the present invention have beendescribed in detail with reference to the drawings, but the specificconfigurations are not limited to these embodiments. Modifications,combinations and deletions of the configurations without departing fromthe spirit of the present invention should be construed as beingencompassed by the present invention. Further, the configurations shownin the embodiments can be combined and utilized as appropriate.

For example, in the first to fourth embodiments described above, thethin film transistor 45 has been taken to be a thin film transistor inwhich an oxide semiconductor is used for the channel layer. However, inthe thin film transistor 45, a silicon semiconductor may be used for thechannel layer.

The liquid crystal driving method of the liquid crystal display devicehas been taken to be a vertical alignment (VA) method, but the drivingmethod is not limited to this. Besides the VA method, liquid crystaldriving methods for the liquid crystal display device can includelongitudinal electric field methods or oblique electric field methods,such as HAN (hybrid-aligned nematic), TN (twisted nematic), OCB(optically compensated bend), CPA (continuous pinwheel alignment), ECB(electrically controlled birefringence), or TBA (transverse bentalignment). A method can be appropriately selected and used.

The black electrodes 4, i.e. the metal layer patterns 2 have been takento be scanning electrodes, and the transparent electrode patterns 6 havebeen taken to be detection electrodes.

However, the roles of detection electrodes and driving electrodes may beswitched. For example, the transparent electrode patterns 6 may serve asthe scanning electrodes, and the black electrodes may serve as thedetection electrodes. Alternatively, in the perpendicular arrangement,the forming directions of the transparent electrode patterns 6 and theblack electrodes perpendicular to each other may be switched.

REFERENCE SIGNS LIST

-   -   1: first light absorptive resin layer pattern    -   1 a, 2 a, 3 a: pixel opening portion (opening portion)    -   2: metal layer pattern    -   3: second light absorptive resin layer pattern    -   5: transparent resin layer    -   6: transparent electrode pattern    -   10: first transparent substrate    -   10 a: main surface (surface)    -   16: auxiliary conductor    -   22, 22A, 22B: substrate for a liquid crystal display device        (display substrate)    -   23, 23B: array substrate    -   24: liquid crystal layer    -   25, 25 a, 25 b: pixel electrode    -   28, 28 a: insulating layer    -   40: metal wiring    -   45: thin film transistor    -   46: channel layer    -   56 a, 56 b: auxiliary capacitance electrode    -   100: liquid crystal display device    -   110, 111, 112: display portion    -   120: control portion    -   B: blue pixel    -   G: green pixel    -   R: red pixel    -   R6, R8: superposed portion (a part)    -   R7, R9: protruding portion (remaining part)    -   X: first direction    -   Y: second direction    -   Z: stacking direction

What is claimed is:
 1. A liquid crystal display device comprising: adisplay unit that has a display substrate, a liquid crystal layer, andan array substrate laminated therein in this order; and a control unitthat controls the display unit and a touch sensing function, wherein thedisplay substrate has a first transparent substrate, and has a pluralityof first light absorptive resin layer patterns having openings formedtherein, a plurality of metal layer patterns having openings formedtherein, a plurality of second light absorptive resin layer patternshaving openings formed therein, a transparent resin layer, and aplurality of transparent electrode patterns that are electricallyisolated, laminated in this order on a surface of the first transparentsubstrate, the surface of the first transparent substrate facing theliquid crystal layer, the plurality of first light absorptive resinlayer patterns, the plurality of metal layer patterns, and the pluralityof second light absorptive resin layer patterns are formed into the sameshape and are in alignment, when viewed in a laminating direction alongwhich the display substrate, the liquid crystal layer, and the arraysubstrate are laminated, the plurality of metal layer patterns arearrayed in a first direction perpendicular to the laminating direction,being insulated from each other, the plurality of transparent electrodepatterns are arrayed in a second direction perpendicular to thelaminating direction and the first direction, being insulated from eachother, each metal layer pattern has at least one of an alloy layermainly containing copper, and a copper layer, the array substrate has asecond transparent substrate, and has a pixel electrode, a thin filmtransistor, a metal wiring, and a plurality of insulating layersprovided on a surface of the second transparent substrate, the surfaceof the second transparent substrate facing the liquid crystal layer, thetouch sensing function at least includes setting the plurality of thetransparent electrode patterns to a constant electrical potential,applying a touch driving voltage across the plurality of transparentelectrode patterns and the plurality of metal layer patterns, anddetecting a change in electrostatic capacitance across the metal layerpatterns and the transparent electrode patterns, and when the liquidcrystal layer is driven, the plurality of transparent electrode patternsare set to a constant electrical potential, a liquid crystal drivingvoltage is applied across the plurality of transparent electrodepatterns and the pixel electrode to drive the liquid crystal layer, anda frequency of the touch driving voltage is different from that of theliquid crystal driving voltage.
 2. The liquid crystal display device ofclaim 1, wherein the array substrate includes the pixel electrode, andan auxiliary capacitance electrode disposed on an opposite side to theliquid crystal layer via the insulating layers contacting the pixelelectrode, wherein each auxiliary capacitance electrode forms, in planview, an overlap with the pixel electrode and an extension of theauxiliary capacitance electrode, the extension being extended from thepixel electrode, wherein the overlaps as well as the extensions areline-symmetrically disposed with respect to a center line dividing theopening into two, and wherein a voltage different from the liquidcrystal driving voltage is applied to each auxiliary capacitanceelectrode.
 3. The liquid crystal display device of claim 1, wherein thethin film transistor includes a channel layer that contains two or moremetal oxides among gallium, indium, zinc, tin, and germanium.
 4. Theliquid crystal display device of claim 1, wherein each metal layerpattern is configured of a plurality of layers, and wherein at least oneof the plurality of layers is the alloy layer.
 5. The liquid crystaldisplay device of claim 1, wherein each metal layer pattern has thealloy layer, and wherein an alloy element contained in the alloy layeris one or more elements selected from magnesium, calcium, titanium,molybdenum, indium, tin, zinc, aluminum, beryllium, and nickel.
 6. Theliquid crystal display device of claim 1, wherein each metal layerpattern is configured of a plurality of layers, and wherein among theplurality of layers, the layer nearest to the second transparentsubstrate is a copper-indium alloy layer.
 7. The liquid crystal displaydevice of claim 1, wherein auxiliary conductors having resistivitysmaller than resistivity of the plurality of transparent electrodepatterns are provided on the transparent electrode patterns.
 8. Theliquid crystal display device according to claim 1, wherein the openingsof the first light absorptive resin layer patterns, the openings of themetal layer patterns, and the openings of the second light absorptiveresin layer patterns are each provided with any of a red pixel formed ofa red layer, a green pixel formed of a green layer, and a blue pixelformed of a blue layer, and wherein the red pixel, the green pixel, andthe blue pixel are inserted between the plurality of metal layerpatterns and the transparent resin layer in the laminating direction,and are arranged adjacently to each other when viewed in the laminatingdirection.
 9. The liquid crystal display device of claim 1, whereinliquid crystal molecules contained in the liquid crystal layer exhibitnegative dielectric anisotropy and are initially aligned in a verticaldirection.